Struct Length

pub struct Length(pub u32);

A type for representing data set content length, in bytes. An internal value of 0xFFFF_FFFF represents an undefined (unspecified) length, which would have to be determined with a traversal based on the content’s encoding.

This also means that numeric comparisons and arithmetic do not function the same way as primitive number types:

Two length of undefined length are not equal.

assert_ne!(Length::UNDEFINED, Length::UNDEFINED);

Any addition or subtraction with at least one undefined length results in an undefined length.

assert!((Length::defined(64) + Length::UNDEFINED).is_undefined());
assert!((Length::UNDEFINED + 8).is_undefined());

Comparing between at least one undefined length is always false.

assert!(Length::defined(16) < Length::defined(64));
assert!(!(Length::UNDEFINED < Length::defined(64)));
assert!(!(Length::UNDEFINED > Length::defined(64)));

assert!(!(Length::UNDEFINED < Length::UNDEFINED));
assert!(!(Length::UNDEFINED > Length::UNDEFINED));
assert!(!(Length::UNDEFINED <= Length::UNDEFINED));
assert!(!(Length::UNDEFINED >= Length::UNDEFINED));

Tuple Fields

0: u32

Implementations

impl Length

pub const UNDEFINED: Self = _

A length that is undefined.

pub fn new(len: u32) -> Self

Create a new length value from its internal representation. This is equivalent to Length(len).

pub fn defined(len: u32) -> Self

Create a new length value with the given number of bytes.

Panic

This function will panic if len represents an undefined length.

impl Length

pub fn is_undefined(self) -> bool

Check whether this length is undefined (unknown).

pub fn is_defined(self) -> bool

Check whether this length is well defined (not undefined).

pub fn get(self) -> Option<u32>

Fetch the concrete length value, if available. Returns None if it represents an undefined length.

pub fn inner_eq(self, other: Length) -> bool

Check whether the length is equally specified as another length. Unlike the implemented PartialEq, two undefined lengths are considered equivalent by this method.

Trait Implementations

impl Add<i32> for Length

type Output = Length

The resulting type after applying the + operator.

fn add(self, rhs: i32) -> Self::Output

Performs the + operation.

impl Add for Length

type Output = Length

The resulting type after applying the + operator.

fn add(self, rhs: Length) -> Self::Output

Performs the + operation.

impl Clone for Length

fn clone(&self) -> Length

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Length

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Length

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<u32> for Length

fn from(o: u32) -> Self

Converts to this type from the input type.

impl PartialEq for Length

fn eq(&self, rhs: &Length) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Length

fn partial_cmp(&self, rhs: &Length) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Sub<i32> for Length

type Output = Length

The resulting type after applying the - operator.

fn sub(self, rhs: i32) -> Self::Output

Performs the - operation.

impl Sub for Length

type Output = Length

The resulting type after applying the - operator.

fn sub(self, rhs: Length) -> Self::Output

Performs the - operation.

impl SubAssign<i32> for Length

fn sub_assign(&mut self, rhs: i32)

Performs the -= operation.

impl SubAssign for Length

fn sub_assign(&mut self, rhs: Length)

Performs the -= operation.

impl Copy for Length